Because they always work problems out with a pencil.
Sits down and works it out with a pencil.
He works it out with a pencil
Guardians of the galaxy
Hnng. Aaaaaaaah. Like that. I'll show myself the door.
A conundrum
Someone who solves a problem you didn't know you had in a way you don't understand.
They get a pencil and work it out.
He couldn't budget.
Sin Pi